Fuses operating optically in the vicinity of the target



Sept. 25, 1962 G. E. GIRAUDO 3,055,303

FUSES OPERATING OPTICALLY IN THE VICINITY OF THE TARGET Filed Jan. 15,1957 N I jf\1o 7 ML 9 TTg 13 8 1,)

INVENTOR Georges Elie GIRAUDO AT ORNEYS Stats Unite 1 3,055,303 FUSESOPERATING OPTICALLY IN THE VICINITY OF THE TARGET Georges Elie Giraudo,24 Rue Caumartin, Paris, France Filed Jan. 15, 1957, Ser. No. 634,238Claims priority, application France Jan. 19, 1956 7 Claims. (Cl.10270.2)

It is a well known fact that fuses may be operated in proximity of thetarget through optic means and that they include to this end a photocelladapted to release the operation of the fuse when the latter issubjected to predetermined luminous, infra-red, ultra-violet or the likerays.

In order that such fuses may operate by night, they may also include anarrangement for producing the desired radiation and this radiationreflected by the target is adapted to release the operation of the fuse.

In order that said fuse may operate without being dis turbed by anyparasitic luminous rays such as the sunrays or the like which riskproducing their untimely operation, it has already been proposed tomodulate said infra-red, or ultra-violet luminous flux and to make useof a photocell detector adapted to operate only when it receives such amodulated luminous or the like flux which is returned onto it by thescreening target in proximity with which the fuse is to explode, themodulation of said returned flux being obviously equal to the frequencyof the flux transmitted by the fuse.

When executing such an arrangement in practice, it is possible tosynchronize for a perfectly stable frequency the modulation of thetransmitted waves and to synchronize similarly the receiving means, butthis requires costly and bulky arrangements.

My invention has for its object to cut out these drawback and to obtaina suitable synchronization between the received waves and thetransmitted waves, said synchronization being sufficient for it to bepossible to obtain the desired result without perfect stability of thetransmitted frequency being essential. This allows using for themodulation of the transmitted waves a simple mechanical arrangementactuated for instance by a mere blade propeller. Under such conditions,my invention consists in obtaining a constant selectivity for thereception to either side of the transmitting frequency, within a band offrequencies of a constant breadth, by resorting to a phase bridge.

Furthermore and preferably, I provide in conformity with my invention apreliminary selection of the received radiation by means of a band-passfilter the breadth of which is selected before operation so as to besufliciently large to cover all modifications to which the transmittermay be subjected in practice.

I have illustrated diagrammatically and by way of example in theaccompanying drawing a preferred embodiment of my invention. The singleFIGURE of the drawing illustrates diagrammatically an arrangementaccording to my invention.

In said figure, 1 designates a mechanical modulator surrounding a sourceof light 2 and driven by a windwheel 3; said modulator may beconstituted for instance by a simple rotary screen cutting offperiodically the beam of light at the frequency provided by thewindwheel. This modulator 1 carries one or more poles of magneticmaterial 4 adapted to move in front of a permanent magnet 5 providedwith a winding 6. The voltage induced in said winding is app-lied to thefeeding of a phase bridge including for instance as well known per se atransformer of which the secondary 7 has been illustrated at 7 while itsprimary 14 is fed by an amplifier filter 13 operating on a broad band offrequencies and following the photocell 1'2. Said band of frequencies isdefined so as to provide for the passage of only those frequencies whichlie within the extreme possible variations of modulation. The phasebridge includes furthermore two dry rectifiers 8 and 8', two resistances9 and 9' and two condensers 1e and 10' connected across the outerterminals of the rectifiers between the two wires 11 and 11, whichrelease in the conventional manner the operation of the fuse at 15.Untimely parasitic optic signals may be produced for instance if thetarget is illuminated by a non-stable light or else if the cell sees,for instance, the visible portion of the objective alternatingly as adark or as a light surface. However, these parasitic optic signalscorrespond generally to a frequency which is very different from themodulation frequency and the phase bridge produces then no signal or ifit did produce a signal, as may occur for certain ratios between thefrequencies involved, it would be necessary for said parasitic signalsto last enough time for the time constant constituted by the associationof the resistances 9-9 and of the capacities 1tl-10 to be loaded, whichis obviously hardly probable. On the other hand, the parasitic signalwill have been relieved of all the frequencies incorporated with it,which are not included within the passing band of the amplifier.

Of course, it is possible to bring numerous modifications to thearrangement disclosed without unduly widening the scope of my inventionas defined in the accompanying claims. In particular, the phase bridgemay be executed in a manner different from that described andillustrated by way of a mere exemplification.

What I claim is:

1. In combination with a fuse adapted to operate in the proximity of thetarget, the provision of a light-controlled fuse operating system,comprising a source of light producing a luminous beam, means forproducing a mechanical modulation of said luminous beam roughly at apredetermined frequency, light sensitive means adapted to receive themodulated beam reflected back by the target and to transform it into anelectric current of the same frequency as that of the beam modulation,means for transforming the mechanical frequency of the beam-modulatingmeans into an electric current of equal frequency, a phase bridgeadapted to superpose said two currents of equal frequencies to produce aunidirectional current and fuse-operating means controlled by saidunidirectional current from the phase bridge.

2. In combination with a fuse adapted to operate in the proximity of thetarget, the provision of a light-controlled fuse operating system,comprising a source of light producing a luminous beam, means forproducing a mechanical modulation of said luminous beam roughly at apredetermined frequency, light sensitive means adapted to receive themodulated beam reflected back by the target and to transform it into anelectric current of the same frequency as that of the beam modulation,means for transforming the mechanical frequency of the beammodulatingmeans into a second electric current of equal frequency, a phase bridgeincluding two rectifying bridge arms each of said bridge arms connectedto the other at one end to form a connecting point, the connecting pointbetween which is adapted to be fed in opposition by the first-mentionedcurrent, the other ends of said bridge arms forming output ends, twocondensers connected in series across the output ends of said arms,resistances connected in series across the output ends of said arms anda diagonal branch-circuit fed by the second current and connecting theconnection point between the rectifying arms with the connecting pointsbetween the condensers and resistances and fuse operating meanscontrolled by the current impulses produced by the superposition of thetwo currents in the phase bridge between the output ends of therectifying bridge arms.

3. In combination with a fuse adapted to operate in the proximity of thetarget, the provision of a light-controlled fuse operating system,comprising a source of light producing a luminous beam, means forproducing a mechanical modulation of said luminous beam roughly at a.predetermined frequency, light sensitive means adapted to receive themodulated beam reflected back by the target and to transform it into anelectric current of the same frequency as that of the beam modulation,electromagnetic means for transforming the mechanical frequency of thebeam modulating means into an electric current of equal frequency, aphase bridge adapted to superpose said two currents of equal frequenciesto produce a unidirectional current and fuse operating means controlledby said unidirectional current from the phase bridge.

4. In combination with a fuse adapted to operate in the proximity of thetarget, the provision of a light-controlled fuse operating system,comprising a source of light producing a luminous beam, a wind-wheel forproducing a mechanical modulation of said luminous beam roughly at apredetermined frequency, light sensitive means adapted to receive themodulated beam reflected back by the target and to transform it into anelectric current of the same frequency as that of the beam modulation,means for transforming the mechanical frequency of the beam-modulatingmeans into a second electric current of equal frequency, a phase bridgeadapted to superpose said two currents of equal frequencies to produce aunidirectional current and fuse operating means controlled by saidunidirectional current from the phase bridge.

5. In combination with a fuse adapted to operate in the proximity of thetarget, the provision of a light-controlled fuse operating system,comprising a source of light producing a luminous beam, means forproducing a mechanical modulation of said luminous beam roughly at apredetermined frequency, a photo-cell adapted to receive the modulatedbeam reflected back by the target, an amplifier fed by said photocell, atransformer fed by the photocell and the secondary of which produces anelectric current of the same frequency as that of the beam modulation,means for transforming the mechanical frequency of the beam modulatingmeans into a second electric current of equal frequency, a phase bridgeadapted to superpose said two currents of equal frequencies to produce aunidirectional current and fuse operating means controlled by saidunidirectional current from the phase bridge.

6. In combination with a fuse adapted to operate in the proximity of thetarget, the provision of a light-controlled fuse operating system,comprising a source of light producing a luminous beam, means forproducing a mechanical modulation of said luminous beam roughly at apredetermined frequency, a photo-cell adapted to receive the modulatedbeam reflected back by the target, an amplifier fed by said photo-celland forming a band pass filter allowing the passage of the range offrequencies corresponding to the rough frequency of the modulation, atransformer fed by said photo-cell and the secondary of which producesan electric current of the same frequency as that of the beammodulation, means for transforming the mechanical frequency of thebeam-modulating means into a second electric current of equal frequency,a phase bridge adapted to superpose said two currents of equalfrequencies to produce a unidirectional current and fuse operating meanscontrolled by said unidirectional current from the phase bridge.

7. In combination with a fuse adapted to operate in the proximity of thetarget, the provision of a light-controlled fuse operating system,comprising a source of light producing a luminous beam, a wind-wheel forproducing a mechanical modulation of said luminous beam roughly at apredetermined frequency, a photo-cell adapted to receive the modulatedbeam reflected back by the target, an amplifier fed by said photo-cell,and forming a band pass filter allowing the passage of the range offrequencies corresponding to the rough frequency of modulation, atransformer fed by the photo-cell and the secondary of which produces anelectric current of the same frequency as that of the beam modulation,electromagnetic means for transforming the mechanical frequency of thebeam-modulating means into a second electric current of equal frequency,a phase bridge including two rectifying bridge arms each of said bridgearms connected to the other at one end to form a connecting point, theconnecting point between which is adapted to be fed in opposition by thecorresponding halves of the transformer secondary with thefirst-mentioned current, the two other ends of said bridge arms formingoutput ends, two condensers connected in series across the output endsof said arms, resistances connected in series across the output ends ofsaid arms and a diagonal branch circuit fed by the second current andconnecting the connection point between the rectifying arms with theconnecting points between the condensers and resistances, and fuseoperating means controlled by the current impulses produced by thesuperposition of the two currents in the phase bridge, between theoutput ends of the rectifying bridge arms.

References Cited in the file of this patent UNITED STATES PATENTS2,137,598 Vos Nov. 22, 1938 2,234,329 Wolff Mar. 11, 1941 2,365,580Murcek Dec. 19, 1944 2,490,899 Cohen Dec. 13, 1949 2,506,946 Walker May9, 1950 2,524,807 Kallmann Oct. 10, 1950 2,632,040 Rabinow Mar. 17, 1953FOREIGN PATENTS 159,501 Australia Oct. 27, 1954 159,839 Australia Nov.17, 1954 268,889 Switzerland Sept. 16, 1950

